Daily Consumption of a Garlic and Onion Extract May Have a Protective Effect Against Respiratory Infections in Elderly Residents of Care Facilities

by | May 26, 2023 | 2023, Aging, Garlic, Lung Health, Respiratory Health

Written by Harold Oster, MD. Results show that daily consumption of a garlic and onion extract concentrate may lower the incidence of respiratory infectious diseases in a population of elderly residents of a care facility, but other factors may have played a role in producing the apparent benefit.

garlicThe population of the United States and the world is aging, and it is estimated that as many as one-third of deaths in the elderly are due to infectious diseases with most being respiratory1. Elderly residents of care facilities are at especially elevated risk of respiratory infections because they have weakened immune systems from underlying diseases, and they are in close proximity to other residents. Influenza, the common cold, Sars-Cov-2, and pneumonia are the most common infections in most institutions2.

Given the significant burden of these infections, there is a need to develop safe strategies for prevention, including dietary supplements. Garlic and onion contain allicin, propyl-propane thiosulfinate (PTS), and propyl-propane thiosulfonate (PTSO), organosulfur compounds known to have anti-inflammatory and anti-microbial properties,3 4 and have long been used for prevention and treatment of inflammatory and infectious illnesses.

Jorge Garcia-Garcia, et al studied the potential effects of garlic and onion extract concentrate on the incidence of respiratory infections in otherwise healthy elderly residents of a single nursing home in Granada, Spain. Sixty-five patients were randomly assigned an extract standardized in organosulfur compounds or an indistinguishable placebo. All residents received influenza and Sars-Cov-2 vaccines. Over 36 weeks, the residents were followed for 14 clinical parameters of influenza-like illness, the common cold, and pneumonia. The primary outcome of the study was the incidence of infections diagnosed by the appearance of symptoms consistent with the illness. Because of rules in place for examining patients during the Covid pandemic, severity of illness was not directly assessed, rather the number and duration of symptoms were used as a marker for severity.

The authors noted the following:

  • Baseline characteristics were similar in the treatment and control groups. Most were over eighty years old, and 80% were female. 86.2% were smokers, and 92.3% were regular drinkers.
  • Consumption of the garlic and onion extract was associated with a lower incidence of respiratory infections.
  • Symptoms were analyzed independently from the overall incidence of infections and were more common in the placebo group than in the treatment group.
  • The severity of illness, defined by the number and duration of symptoms, was lower in the treatment group.

Results of the study suggest a benefit of a garlic and onion extract in preventing and decreasing the severity of respiratory infections. The study has several limitations. It was performed at a single center in Spain with a small number of residents, and a far greater percentage of participants smoked and drank regularly than in the general population, both factors that increase the risk and severity of respiratory infections5,6. The distribution of smokers and drinkers was similar in the two groups, but the high percentage would tend to increase the total number of infections and symptoms, exaggerating a benefit that might have been smaller in the general population. Because participants were not directly examined, some reporting numerous symptoms appearing over several days may have been labeled as having multiple or severe infections when an examination would have shown they had only one mild infection.

Source: García-García, Jorge, Carlos Gracián, Alberto Baños, Enrique Guillamón, Julio Gálvez, Alba Rodriguez-Nogales, and Juristo Fonollá. “Beneficial Effects of Daily Consumption of Garlic and Onion Extract Concentrate on Infectious Respiratory Diseases in Elderly Resident Volunteers.” Nutrients 15, no. 10 (2023): 2308.

© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

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Posted May 26, 2023.

Harold Oster, MD graduated from medical school in Miami, Florida in 1992 and moved to Minnesota in 2004. After more than 25 years of practicing Internal Medicine, he recently retired. Dr. Oster is especially interested in nutrition, weight management, and disease prevention. Visit his website at haroldoster.com.

References:

  1. Kline KA, Bowdish DM. Infection in an aging population. Curr Opin Microbiol. Feb 2016;29:63-7. doi:10.1016/j.mib.2015.11.003
  2. Childs A, Zullo AR, Joyce NR, et al. The burden of respiratory infections among older adults in long-term care: a systematic review. BMC geriatrics. 2019;19(1):1-10.
  3. Ankri S, Mirelman D. Antimicrobial properties of allicin from garlic. Microbes Infect. Feb 1999;1(2):125-9. doi:10.1016/s1286-4579(99)80003-3
  4. Cascajosa-Lira A, Prieto Ortega AI, Guzmán-Guillén R, et al. Simultaneous determination of Allium compounds (Propyl propane thiosulfonate and thiosulfinate) in animal feed using UPLC-MS/MS. Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. Nov 2021;157:112619. doi:10.1016/j.fct.2021.112619
  5. Simet SM, Sisson JH. Alcohol’s Effects on Lung Health and Immunity. Alcohol Res. 2015;37(2):199-208.
  6. Jiang C, Chen Q, Xie M. Smoking increases the risk of infectious diseases: A narrative review. Tob Induc Dis. 2020;18:60. doi:10.18332/tid/123845